Glass containers are mainly used for powdery or solid pharmaceutical preparations containing antibiotics, e.g. cefazolin, ampicillin, etc., or enzymes, e.g. urokinase etc., as active ingredients, while containers made of almite (aluminum with a surface oxide film), hard glass, stainless steel, or the like are used for accommodating the starting materials or synthetic intermediates of drugs and the so-called bulk substances.
However, containers made of such materials are disadvantageous in that the drugs contained are liable to become contaminated with metal or glass fragments upon unsealing.
Recently, containers made of glass (borosilicate glass, soda-lime glass) plus rubber, elastomeric closure or the like came into usage but they were also found to have the disadvantage that the antioxidant, e.g. 2,6-di-t-butyl-4-methylphenol (BHT), vulcanizer, adipic acid derivative, phthalic acid derivative, and other additives, as well as the lubricant oil, e.g. silicone oil, tend to emigrate from the rubber or elastomeric closure and become adsorbed on the drugs to cause insoluble particulate matter.
Research is also being done into the use of plastics for pharmaceutical containers, but polyvinyl chloride (PVC), for instance, has the drawback that additives such as dioctyl phthalate (DOP) contained may dissolve out into the interior of the container, while nylon, polyurethane, ethylene-vinyl acetate copolymer (EVA), etc. have the disadvantage that the residual unreacted monomer or monomers tend to prevent formation of a homogeneous solution of the powdery drug. Furthermore, while an adhesive is used in the manufacture of containers from nylon, polyurethane, etc., the solvent used in the adhesive, such as methyl ethyl ketone, toluene, or xylene, diffuse out and become adsorbed on the drug as it is the case with said unreacted monomers, thus causing decomposition, degradation, insoluble particulate matter, and other troubles inclusive of toxic interactions.
The feasibility of using polyolefins such as polyethylene and polypropylene is also being assessed by the industry and their usage for pharmaceutical containers is being spreading but these materials also have the disadvantage that the process-derived contaminants such as adipic acid or phthalic acid derivatives, oils, low molecular substances, the so called wax component, etc. tend to be adsorbed on the drug powder contained and when the drug powder is dissolved in a solvent such as water for injection, give rise to insoluble particulate matter.
Thus, each of the known materials for pharmaceutical containers has its own drawbacks and, therefore, a demand exists for a new method of overcoming said disadvantages and a new kind of drug container which is free from the disadvantages.